Group-based educational interventions on health promotion for people with early-stage dementia have shown promising results. The aim of this study was to explore the associations between sociodemographic characteristics (e.g. sex, education, marital status) and outcomes of a 12-week group-based educational intervention on health promotion for people with early-stage dementia. Secondary analysis of data from the project 'Health promotion for persons with dementia: Prevention of hospitalisation and nursing home replacement for persons with dementia,' a single group, pre-test/post-test intervention study was conducted. Linear regression analyses were used to assess the associations between changes in the primary outcome of the intervention from baseline to post-intervention assessment and the participants' sociodemographic characteristics. Multiple linear regression analyses showed a statistically significant association between improvement in scores on the Cornell Scale for Depression in Dementia (CSDD) post-intervention and level of education ([beta] = -0.209, SE = 0.08, p = 0.013). More specifically, the results show that the scores on the CSDD from baseline to post-intervention improved more in participants with primary and secondary education than in those with tertiary education. The study attracted a high proportion (49%) of individuals with a higher level of education. The findings highlight the need for more knowledge on how to reach people with dementia with all levels of education and the need to consider the knowledge and support needs of various subgroups of people with early-stage dementia when developing and delivering this type of intervention.